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9488585b21
Currently to read a response from the TPM device an application needs provide big enough buffer for the whole response and read it in one go. The application doesn't know how big the response it beforehand so it always needs to maintain a 4K buffer and read the max (4K). In case if the user of the TSS library doesn't provide big enough buffer the TCTI spec says that the library should set the required size and return TSS2_TCTI_RC_INSUFFICIENT_BUFFER error code so that the application could allocate a bigger buffer and call receive again. To make it possible in the TSS library, this requires being able to do partial reads from the driver. The library would read the 10 bytes header first to get the actual size of the response from the header, and then read the rest of the response. This patch adds support for partial reads, i.e. the user can read the response in one or multiple reads, until the whole response is consumed. The user can also read only part of the response and ignore the rest by issuing a new write to send a new command. Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
34 lines
943 B
C
34 lines
943 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _TPM_DEV_H
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#define _TPM_DEV_H
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#include <linux/poll.h>
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#include "tpm.h"
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struct file_priv {
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struct tpm_chip *chip;
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struct tpm_space *space;
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struct mutex buffer_mutex;
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struct timer_list user_read_timer; /* user needs to claim result */
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struct work_struct timeout_work;
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struct work_struct async_work;
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wait_queue_head_t async_wait;
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size_t response_length;
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bool response_read;
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bool command_enqueued;
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u8 data_buffer[TPM_BUFSIZE];
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};
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void tpm_common_open(struct file *file, struct tpm_chip *chip,
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struct file_priv *priv, struct tpm_space *space);
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ssize_t tpm_common_read(struct file *file, char __user *buf,
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size_t size, loff_t *off);
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ssize_t tpm_common_write(struct file *file, const char __user *buf,
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size_t size, loff_t *off);
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__poll_t tpm_common_poll(struct file *file, poll_table *wait);
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void tpm_common_release(struct file *file, struct file_priv *priv);
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#endif
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